Don't Look Back
by FlamingDiskord
Summary: Marceline and Marshall Lee move to Ooo after a tragic event in their old home. How will they take to living under the supervision of the Bubblegums? Rated T for now but subject to change in later chapters.
1. Introduction: Arriving in Ooo

**Hello Everyone! This is a story centered around PB and Marceline and their lives growing up around each other, in a parallel universe to the one in which AT is normally set. This is my first fic, so constructive criticism is wwelcomed as are suggestions.**

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The pale twins took a final step off the bus that had taken them from their old home in the City of Aaa to the City of Ooo, the journey took them across many boarders. Some were shut behind them not to be reopened. Return was practically impossible. They were stuck in Ooo. Marshall Lee, the older of the two (by 3 seconds) took a step toward a tall, strong, pink man before them. Marceline followed in suit dragging her luggage behind her. As they neared the man Marceline realized that he wasn't alone, and that behind him was a little pink girl around the same age as her clutching her fathers leg. Marceline snickered a little. The girl and her father were both wearing pink clothes that almost matched their complection. But she couldn't help but notice the clothes they wore we're of considerably better quality than hers. 'They must be rich' Marceline concluded.

Marceline knew that her father was rich, but she'd never really seen the money. Her mother had raised the pair by herself while her father rarely came home. It wasn't that he didn't like his family. It was just his job kept him away for almost years at a time. Marceline could count the times she had seen her father for more than 3 days at a time on two hands, and she was six. But this never really bothered her. Her mother was amazing and always made the pair feel loved. Life had been hard for their family as Marcelines father for some reason beyond her child understanding her father couldn't send lots of money at a time. This meant they lived in almost poverty. That was until three weeks ago when a conflict broke out in Aaa. Marceline's mother had been with her father for the weekend. When she had come rushing through the front door in clothing that covered almost all of her figure. Marceline could only see her mothers eyes as she scooped them both up pulling them from their house and into a family car. She'd then run back inside and grabbed all of the twins possessions and placed them in suitcases. They quickly departed their home. But before either of the children could ask why they'd left, the sky behind them blew up in a plume of smoke and bright orange light, brought on by massive pillars of fire. The car speed away from the evermore frequent flashes of light and fire that covered the city. They drove for a long time before they reached a large building close to the border of of Aaa. Even with the distance between them and the city the rumbling could still be felt through the ground and orange light seen on the horrison. Their mother stepped out of the car and pulled up her large sun-hat slightly, and pulled down her collar so her face could be seen as she retrieved the twins and their suitcases. Marshall could see her mother had been crying but being the more sensible of the pair withheld any questions. Their mother led them into the building and stopped in the lobby. Kneeling down to face the children and putting a hand on each of their shoulders.  
'Marshall Lee, Marceline, I have to go away for a while. *sniff* But I'm leaving you here just for a little while your father and I *sniff* sort some things out.' their mother had tears freely rolling down her cheeks now. 'N...*sniff* Now if I d-don't come back in two weeks time, or something happens to me. You'll be going to live with a very close family friend, Mr Bubblegum. But I promise you. Nothing bad will happen to you while your with him. Or while you are here. Just promise me. *sniff* T-that you'll be on your best behaviour. D-don't m-muck around. And Mar-...' their mother has begun to sob uncontrollably as her throat got caught on the word. 'Marce, l-listen to y-your brother.' she said eyes tightly shut. 'S...stay with each other and look o-out for each other.' she pulled her children into a tight hug. Kissing the both on the forehead. 'And remember. I-I will... I will ALWAYS love you both.' she said standing up taking a deep spluttering breath. She walked towards the door, and turned back to her children, that were also crying wondering why this was happening. She felt a massive pang of guilt strike inside her heart as it slowly broke at the sight of her children. She knew this was the last time she would see them. Their father would be there with financial support. But she knew they were on their own. The Bubblegum's had done her an un-repayable favor with promising to raise her children as he would his own. And for that she would be eternally grateful. She'd know this part would be hard. But the difficulty of leaving her children was nothing she could have prepared for. Her last words to them were. 'Mr Bubblegum will take care of you and treat him... treat him like you would do to m-me. And never ever doubt that I don't love y-you. I will always care for you and don't forget that you will always have each other to r-rely on. I love you both so much. Goodbye my darlings.' she said turning towards the door and leaving the building trying her hardest not to look back.  
'Goodbye mum.' Marceline said quietly  
'Well miss you' finished Marshall.  
Their mum had almost broken down then and there. But she kept going not daring to look back at them. She got into her car and drove. Drove non stop until she reached her husband. Crying the entire way there. Knowing exactly what the future held for her.

Two weeks later the twins had been informed that their mother had died. The orphanage they had been staying at contacted Mr Bubblegum and told him the twins would arrive within the week. And soon the twins were on a bus with nothing but a few clothes and toys from their former life. Only wishing that it could have stayed the way things had been.

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**Hope you enjoyed the first chapter! Let me know if you enjoyed it and you should hear from me soon! :)**


	2. Chapter 1: Settling In

**A/N Hey everyone. Thanks for being patient and waiting. I know this update has taken a while but I had some serious trouble thinking up this chapter and I would like to thank my editor Turbosloth so much for actually making this chapter bearable. I would also like to thank everyone who reviewed the story or PM'ed me, it means a lot, so thanks. And finally I don't own Adventure Time.**

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Chapter 1: Settling in.

The twins were closing in on the pink man waiting for them. It was only then Marceline noticed something and Marshall had seen it too. They both stopped dead in their tracks, an uncomfortable gap between the two.  
Marshall turned to his sister with considerable bewilderment. 'He's made of gum.'  
Marceline couldn't find any words and just found herself getting confused about how in front of her was living, breathing gum... with a daughter.  
Mr Bubblegum smiled at the children, obviously having seen their reaction. He closed the distance between them and eagerly held out his hand. Marshall boldly shook it first followed by the slightly more hesitant Marceline. 'Hello children. I'm Mr Bubblegum, and I'm going to be your guardian. I was a very close friend of your mother when she was younger. Oh, and before you have to ask, yes, I am made of gum, and this is my daughter.' He moved aside to reveal the young girl behind him, who stood up as tall as she could and stepped forward. She was obviously trying hard to make a good impression.  
'I'm Princess Bubblegum, I'm 5 turning 6 in a few weeks, I live with my family and I am about to start attending our local primary school.' she said with a chirpy I-learnt-my-public-speaking-at-school voice.  
'Ahh, hi, Princess Bubblegum' Marshall said, trying to appear confident but failing miserably. 'I'm Marshall Lee. This is my sister Marceline. We're from Aaa, and are coming to live here with you. Well at least that's what we've been told.'  
'Right you are!' Mr Bubblegum said, taking a small step forward to pick up the twins bags. Marceline was slightly reluctant to hand her belongings over, not quite trusting this strange man yet. 'First order of business is to take you to my house where I have to sort a few things first, then we can go and get you some new clothes and things for new school. But we can talk about that more at the house! Follow me." He quickly turned around and headed for a large family car parked down the road. Marshall followed right behind him, leaving Marceline and the Princess at the back of the group. Marceline decided that maybe it was a good idea to talk to the gum girl, to find out some stuff about who she would be living with.  
"Sooo, are you a real Princess?" She asked hesitantly, not sure how to start things off.  
The princess giggled and pointed to her crown.  
"Of course I am. My daddy is the ruler of Ooo."  
"Wow, really?"  
"Yep! The Bubblegums have ruled since the ending of the Mushroom War."  
Marceline's jaw dropped. She'd just been adopted by a royal family.  
"Wait, what's the Mushroom War?"  
"You don't know what the Mushroom war is?" The Princess looked incredulous.  
"Well, ah, no-"  
Marceline began, feeling like she was slightly too dumb to even be talking to her, before she was cut off by Mr Bubblegum.  
"Here we are," he called back as he motioned towards the big family sized vehicle. "Everyone in. Hey Marshall, do you wanna sit in the front with me? Give the girls some time to chat. I'll tell you about my son."  
"Yeah! That'd be math!" Marshall hoisted himself up onto the passenger seat and strapped himself in. The princess motioned for Marceline to enter the back first. Giving a quick nod she found her seat, the princess close behind pulling the door shut. She slid across the luxurious leather that covered every surface of the car. The king stored the twins belongings and casually got into the drivers seat after doing a quick check of the children's seatbelts.  
"Good everyone's in. So Marshall-"  
The car started moving, purring along the road. Marceline felt a small tap on her arm. She turned to see radiant smile of the princess.  
"Your gonna love your new home. It's got everything. TV, computers and your bed will be a bunk bed!"  
Marceline looked at the girl confused, feeling even more inadequate than before.  
"Ahh, princess I don't know what those are. I've heard of TV, but we didn't have one and we only had one bed. What's a bunk bed? And a computer?"  
PB's smile fell.  
"Oh, I'm sorry. Things must be different in Aaa. These are fun things, you know, stuff to keep you entertained. If you didn't have those, what did you do for fun?"  
Marceline shrugged.  
"I just played with Marshall. He's an awesome brother, we pulled all these wicked pranks together. And then there was Hambo. He's a toy our babysitter gave us before he had to go. I'd just play with them when I was bored. They're my friends."  
"Did you have anyone else?"  
"Nope. That's it."  
PB felt bad for the girl. Only two friends.  
"Well what about your babysitter?"  
"Simon? He had to go, in the last few weeks he was with us, he started to act weird and one day it was like he just forgot us. My m-mum" she stumbled over the words as the loss threatened to overtake her again, as it had many times, "c-came home and f- found us alone when she got home and we never saw him again."  
The princess' eyes were wide. This girls life had been terrible. Not to mention she hadn't even heard anything about her parents and she was here because she was an orphan. PB decided not to pry. She'd had enough of the sad subject of this girls life and was determined not to let it get her down.  
"So, ah, let me tell you about TV-"  
Marceline listened with great interest the princess explained TV and the Internet. How computers and bunk beds worked. "It's a bed, with a ladder!" Marceline found herself liking the company of the girl after the slightly awkward beginnings of what was now a firm friendship after the princess had posed the question of "do you want to be my friend", a question asked by 6 year olds everywhere, after Marceline finished telling a story of a prank she'd pulled. The girls exited the car laughing as they pulled up to a long driveway out of the biggest house Marceline had ever seen. They walked inside and were immediately greeted by a small butler dressed in red and white. Marceline was awestruck by the room. It was massive and intricate. And everything was made of candy. This was not a subtle room.  
"Welcome home everyone. I'm Peppermint Butler. Miss Bubblegum, I need to escort you to your Piano lesson. You're almost late," he chided.  
PB turned to the group.  
"Sorry I have to go. Have fun settling into your new house. I'll come visit tomorrow!"  
As the princess left Marceline and Marshall found themselves looking at each other in confusion. What had she meant by visiting tomorrow? Surely they were staying here. Mr Bubblegum picked up on the pairs confusion.  
"If you two would follow me to my study I will explain everything."  
He said, once again taking the lead up a large rockcandy staircase. They entered a room a lot smaller than the entrance hall. The walls were lined with bookshelves and in the center of the room was a giant toffee table. Mr Bubblegum took a seat facing the twins.  
"Look, I know this has been a hard and confusing last few weeks for the two of you. So if you have any questions feel free to ask them. Now, after I'm done explaining our situation I'm going to take you to your new home, out in the grasslands. It's really close by and you'll have no trouble getting from here to there if you need anything, but for now I need to introduce you to your supervisor."  
Mr Bubblegum reached under his desk and lifted up a little green rectangular device.  
"His name is Beemo, and he'll be taking care of you. He can contact me at any time and I trust him completely. Say hi Beemo"  
The screen of the device flickered and a small face appeared.  
"Hello! I'm Beemo! I am sworn to protect you." It recited in a superhero-like robotic tone.  
Marceline giggled and took an instant liking to him. It was pretty cute.  
"Now," continued Mr Bubblegum. "let's get going. We need to unpack your things and get you settled in. Tomorrow we're going to take you out shopping for some new clothes and show you around the city. Sound good?"  
"Yep." the twins said in unison.  
"Good. Okay back to the car."  
The twins followed the king back to the car, taking up their original seats, Marceline alone in the back. They drove for about two minutes before arriving at a giant treehouse. Marceline had seen a few big trees before but none even came close to this one. They retrieved their bags and walked inside, taking in their new home. After a quick tour of the facilities they were shown their room. It was slightly larger than Mr Bubblegum's study and had a massive window looking out into a picturesque hilly plain. They quickly organized their few belongings. Mr Bubblegum almost had a heart attack when he saw Marceline pull her Axe-bass from her bag and Marshall doing the same bit with an Axe-guitar. Mr Bubblegum whispered to Beemo about not letting them use them as actual weapons. After a short talk on how to properly use things like the TV, Mr Bubblegum left telling them to be up by 10:30 and that Beemo would wake them. Wishing them a good night, he drove back towards his house, leaving the twins in Beemo's care. Marceline found Beemo was sporty and kind and loved the charismatic box, while Marshall Lee would be constantly trying to sneak attack the console and get into play fights with it.  
After a few hours of mucking around and watching TV, the twins retired to their room. Marceline hopped into the top bunk and pulled Hambo in close. She felt slightly cold and alone in this strange house. It wasn't fun in the dark. She wondered if she would ever see her old house again. She shook off the thought and instead cast her mind to her new home and what she would talk about with her new friend tomorrow. How exploring the city would be. Getting actual clothes. Eventually her train of thoughts reached their respective termini and she fell asleep. Come next morning she woke up to an insistent beeping sound from the little robot, signalling the start of a new day.

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**A/N: Thanks for reading chapter one. Tell me what you liked and didn't like, but please be constructive with your criticism. If you have any ideas you want to share with me you can leave a review or PM me, or find me on Tumblr, just look for FlamingDiskordIMP and you should find me. I would again like to apologize for how long this took to finish but with any luck the next chapter will be up pretty soon. Thanks for reading! ~FlamingDiskord **


	3. Chapter 2: New Clothes

**(A/N) Wow, it's been a while, and for that I'm REALLY sorry. Not a single night when by when I wasn't thinking about this story and the time it was taking. It was just that life got in the way with the end of the school year, exam revision, exam week, thinking about work experience, holidays starting and not to mention my internet going down for 4 and a 1/2 days. But the whole time I was trying to set aside time for this. Anyway thank you for sticking with this and the encouragement you have given me in the comments and a huge thank you to my editor TurboSloth for making this chapter a ton better than it originally was.**

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**Chapter 2: New Clothes**

**Marceline rubbed her eyes. The sun streamed through the blinds and lit up the room. This was the first time Marceline had woken up in a bed that she could call her own, in a room that was actually a desperate room.****  
****She wasn't sure if she was still dreaming. It was a lot to take in, especially early in the morning.****  
****She sat in her bed for a minute and watched the world go by outside her window. Meanwhile Marshall Lee had gotten up and prepared their breakfast. He returned with two bowls of cereal. **

**"Breakfast. Oh, and Beemo said that we could eat in our rooms today and we should take things slow."****  
****Marshall handed her a bowl of what looked like little puffy balls of chocolate that were slowly being drained of their colour, while the milk around them turned brown.**

**"Ah, cool, I guess. What time is it?"**

**"It's 10:45. Beemo said to eat up and get changed soon, Mr Bubblegum will be around shortly."**

**"Mmhhm." Marceline ate the chocolate cereal. She'd never eaten something as tasty as it before and was reminded of the flavorless, bland food she had been eating mere months ago. Marshall sat down on the bed and they both ate in silence slowly coming to terms with this violent upheaval in their lives.******

**Marshall was the first to get moving. He had always been a better mornings person. He left the room to get ready for their big day out and returned in his only pair of clothes. He'd had them for a long time, before their mother had died. Marceline grabbed her equally old clothes from her drawer and entered the bathroom. She undressed and entered the large shower. She stood there for a moment looking at the strange mess of pipes and noticed a lever hidden amongst it. She pulled it outwards and a blast of freezing cold water came out drenching her instantly. She stifled a scream and pushed the lever towards the red on the gauge. The temperature rapidly rose and Marceline relaxed in the new-found warmth. 'Good' she thought 'Red means hot, blue means cold. I can remember that.' She looked around. She saw a small oval pink block on a shelf in the shower. She picked it up, first sniffing it then, put it under the water. It smelled like strawberries and bubbled under the water. Doing what seemed like the funnest option she lathered it over herself and jumped back into the water entertained by the bubbles as they swirled down the pipe.**

**"Showers are the BEST! Baths are nowhere near as good as these! And now I smell like strawberries! This is awesome!"****  
****She shut off the water and stepped out of the shower, quickly drying herself off with a conveniently placed towel. She wiped the steam off the mirror and looked at her reflection. She could see that a lot of the dirt that was on her before had washed away and she felt like it was a stranger looking back at her with its blueish complexion. She tried to flatten her hair but gave up after it resolutely kept popping back up in little clumps. Marceline put on her old clothes and went back into the living room of the house. It wasn't long before the doorbell rang.****  
****Marceline opened it to find a slightly smaller pink girl in a pink dress in front of her.**

**"Hey Marcie!" she said giving her friend a hug and sweet smile. Marceline was still disoriented at this happy, bubbly thing that had appeared at the door and awkwardly returned the hug.**

**"Hi... Princess."****  
****PB broke the hug but held her friends hand looking over her shoulder at the parked car with her dad and brother visible in the front.**

**"We need to get going. We need to get you some new clothes. Come on!" PB shouted enthusiastically pulling Marceline towards the car.****  
****PB pulled open the back door and bundled herself in. Marceline got in herself and found herself looking at the pleasant visage of their driver, none other than Mr Bubblegum himself.**

**"Hiya Marceline how are you today?"**

**"I'm good Mr Bubblegum. The treehouse is amazing and its-its just so cool!" She said, stumbling over the words in her excitement.**

**"That's good to hear. So Marceline this here is my son, Prince Gumball. He's a few months older than you. Gumball, Marceline. Marceline, Gumball." He said, motioning towards a friendly but uptight looking guy sitting in the front of the car.**

**"Hello Marceline it's a pleasure to meet you. My sister wouldn't stop talking about how you two are going to be best friends-"**

**"Hey!" yelled PB before her brother could say more as he stifled a snicker.**

**"That's enough, Gumball" said Mr Bubblegum pointing a stern finger at Gumball. Marceline looked at PB, who had turned away and had a definite red hue to her pink skin, embarrassed and angry at her brother.**

**"Don't be embarrassed, I know how brothers are. I mean if you wanna be best friends, umm well, I'm okay with that, I mean you're my only friend so no competition right?" Marceline muttered shyly.****  
****PB turned back to her smiling a 1000 watt smile.**

**"Thanks Marceline, I'd love to be best friends with you."****  
****Marshall Lee finally entered the car and took his seat next to Marceline, who quickly broke eye contact with PB. **

**"Hey Marshall, this is my son, Gumball, who I was telling you about yesterday."**

**"Hey I'm Marshall."**

**"Nice to meet you, are you ready to get some cool new clothes?"**

**"Glob Yeah!"**

**"Punch it, dad!"**

**Mr Bubblegum started the car and rumbled towards the city. During the journey, the boys started to talk about the different types of cars they could see flying past the window and the girls talked about their interests in music.****  
****It was a short trip into the city. Everywhere they could see the mad bustle of people going about their daily business. Marceline and Marshall were instantly awestruck at the gigantic buildings that loomed over them. Marceline stared out the window, mouth agape. She hurriedly closed it when a giggling PB waving a hand in front of her face.****  
****They twisted and turned down narrow streets until , without warning, Mr Bubblegum sent the car into a deep dark cave. Marceline's eyes acclimatised to the sudden darkness, and saw the lurking shapes of line after line of parked cars. It turned out that this was the department stores underground parking lot. In Marceline's eyes it was just about the coolest thing ever, having a cave under your giant building just for cars. Let alone having a large see-through glass box take you up through the levels of the store. Whole floors were dedicated to women's clothes, men's clothes, baby clothes, toys and games. The pair looked with starstruck eyes at the mass of products arranged before them. The box slowed down and deposited them at the floor for children's clothes.**

**"Okay" said Mr Bubblegum turning to the children. "You can run off and find a few things you like and bring them back here, then we'll see which ones actually fit you. Sound good?" It was clear from his tone that Mr Bubblegum had often had to moderate children's spending spree's.****  
****Everyone nodded.**

**"Great! Off you go."**

**The boys began walking towards their section and PB once again took Marceline's hand and pulled her towards the girls clothes.****  
****The majority of the clothes were a shade of pink that could scorch retinas. It was a colour that Marceline ****_kind of_****liked, but she preferred the darker colours that resided in the women's and older girls section. It wasn't long before Marceline had gotten slightly bored of the slight variation between the dresses and shades of pink and found some of the darker t-shirts for older girls. She and Bubblegum flipped through them until one caught her eye. It was a plain black shirt with a design of a snake weaving it's way through two marshmallows impaled on sticks. She instantly adored it. She pulled it off the rack to see if it fit. It was clearly far too big for her and PB laughed when she saw it reach Marcelines knees. Flustered she tried to find a size that wouldn't make her look like a child wearing their dads shirt. Sadly it was the only one, but Marceline was determined to get it no matter what.******

**They returned with the shirt and Mr Bubblegum just smiled.**

**"Do you want this shirt Marceline? It's pretty big."**

**"I know it's a bit big but I really want it and it's the only size."**

**"Hmmm, okay. We can get it. But I'm going to come over there and help you pick out some clothes that won't trip you if you decide to walk while wearing it."**

**"Okay" Marceline agreed reluctantly.**

**Mr Bubblegum laughed and walked them back over to a secluded corner of the girls section, where he picked out a simple dark purple dress and another light blue one. Marceline wondered how she had missed all the great clothes that were here. They picked up some clothing essentials, and then went back to meet the boys. Marshall had picked out some typical black shorts and shirt couldn't have failed to make him look good.**

**"****So you both happy with your new clothes?" They both nodded. "Good" Mr Bubblegum chuckled jovially and proceeded to pay for the clothes. He handed them back to the children telling them to change into their new clothes for the rest of the day.****  
****The pair changed into them and looked at themselves with wonder. Out of their well worn rags and in their new clothes, they looked practically unrecognizable. Marceline twirled around, watching her new dress move bewitchingly in the light. She gripped her new T-shirt tightly in her hands. Out of the corner of her eye she saw PB stare at her. Marshall strutted past and got some well deserved compliments from Prince Gumball. **

**"Alright kids, come on, we've got lots of things to do today and not much time." Mr Bubblegum said, a happy twinkle in his eye. Obediently they traipsed back to the car and got in. "Alright, now for a tour" he announced, and put the car in gear and pulled back out into the light and onto the busy street.**

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**(A/N) Hope you enjoyed this chapter its a 2 parter and the next chapter should be up really soon so hang tight. Thank you everyone for commenting and Doodle0505 for the one shot idea it may even happen. So if you have any suggestions for things you can contact me through the comments and PM's I read all of them and will always try to respond. You can also contact me through ways listed on my profile. So, thanks for reading and have a good relative time of day. (Man I'm bad at these) **


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